Plants may be subjected to a wide variety of stress conditions that are induced by non-living agents or circumstances such as drought, enhanced salinity, temperature stress, and the like. Deviations from the norm in either direction will constitute an abiotic stress. It is understood that hyper salinity and drought lead to oxidative stress through the accumulation of reactive oxygen species (ROS) and metabolic changes in the plant will generally arise as a result of these stress conditions. A general discussion of genes that are regulated in response to stress is set forth in U.S. Patent Publications 2002/0160378 and 2004/0009476, which appear to be based on the same application.
The present inventors, in an article appearing in 2003 (Liao, H, et al., GENE (2003) 318:103-111) cloned and sequenced a novel purple acid phosphatase-like gene in soybean, designated GmPAP3 that was induced by enhanced salinity, but not by phosphorus deficiency as were many PAP genes. The authors further noted that the nucleotide sequence encoding this protein included a putative mitochondrion targeting transit peptide (MTTP) and speculated that the protein would reside mainly in the mitochondrion.
It has now been confirmed that the expressed GmPAP3-encoded protein is located in mitochondria and can confer tolerance of plants or plant cells with respect to abiotic stress conditions.